The FDA requires that shellstock tags be attached to a container of shellfish until the container is empty, then retained for 90 days. This requirement is based on the National Shellfish Sanitation Program Guide for the Control of Molluscan Shellfish.
The Spokane Regional Health District advises that this 90 day requirement allows time for viruses and parasites to incubate or reach maturity. According to FDA guidelines, shellstock tags must also contain information about how the shellfish was harvested, transported and processed. Along with federal requirements, each state or county may have their own additional guidelines, so it is important for all retailers and restaurant owners to check all local and state regulations as well.